Filter cartridges include valves which perform several functions such as a bypass function when the filter media becomes clogged and an anti-drainback function to prevent oil from leaving the filter cartridge when the engine with which the filter cartridge is connected is not running. An additional need is to provide a clean side valve which prevents drainback of clean fluid from an installed filter cartridge. There is another need because filter installers occasionally fill a new filter cartridge with unfiltered oil or fuel prior to installation of the new filter cartridge.
During manufacture, when dispirate parts are matched, the risk of failure is increased because one of the parts may be of inferior quality and adversely effect the reliability of the entire assembly. It is frequently time consuming and therefore costly to assemble the plurality of elements in order to configure an item reliably. Consequently, utilizing only a single element can then be advantageous. This is especially the case with mass produced items such as filters for engine lubricating oil which are manufactured by the millions.